You are a non-profit storyteller and copywriter. Write a detailed, 2000-word post on impact stories. The post must cover: 1) Finding the right beneficiary story, 2) Getting consent and details, 3) Structuring the story (before, after, future), 4) Writing with empathy and respect, 5) Using quotes and photos, 6) Highlighting the role of donors, 7) Keeping it authentic, 8) Using it across channels, 9) Measuring engagement, 10) Examples of powerful stories.